Digest: Theoretical advances in studying selection via microbiome-mediated traits

How do microbes associated with multicellular hosts contribute to host evolution, and how do factors such as mode of transmission mediate these contributions? Week et al. (2025) provide a theoretical framework to address these questions and through simulation show that microbial transmission mode can have varying effects that interact with host life history. This expands our potential to understand host-microbiome dynamics and illustrates that a quantitative genetic framework provides a more accurate view of organismal evolution than correlative analyses of siloed datasets.